scholarly journals Near-IR Emitting Si Nanocrystals Fabricated by Thermal Annealing of SiNx/Si3N4 Multilayers

2019 ◽  
Vol 9 (22) ◽  
pp. 4725
Author(s):  
D. M. Zhigunov ◽  
A. A. Popov ◽  
Yu. M. Chesnokov ◽  
A. L. Vasiliev ◽  
A. M. Lebedev ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
X Ray ◽  
Near Ir ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Mean Size ◽  
The One ◽  
Multilayered Thin Films

Silicon nanocrystals in silicon nitride matrix are fabricated by thermal annealing of SiNx/Si3N4 multilayered thin films, and characterized by transmission electron microscopy, X-ray reflectivity and diffraction analysis, photoluminescence and X-ray photoelectron spectroscopy techniques. Si nanocrystals with a mean size of about 4 nm are obtained, and their properties are studied as a function of SiNx layer thickness (1.6–2 nm) and annealing temperature (900–1250 °C). The effect of coalescence of adjacent nanocrystals throughout the Si3N4 barrier layers is observed, which results in formation of distinct ellipsoidal-shaped nanocrystals. Complete intermixing of multilayered film accompanied by an increase of nanocrystal mean size for annealing temperature as high as 1250 °C is shown. Near-IR photoluminescence with the peak at around 1.3–1.4 eV is detected and associated with quantum confined excitons in Si nanocrystals: Photoluminescence maximum is red shifted upon an increase of nanocrystal mean size, while the measured decay time is of order of microsecond. The position of photoluminescence peak as compared to the one for Si nanocrystals in SiO2 matrix is discussed.

Nanofiber Based Er(III) Metal Pyrochlore Oxides: Synthesis and Characterization

2007 ◽  
Vol 1023 ◽  
Author(s):  
Ruofeng Wang ◽  
Edward T. Bender ◽  
Mohannad T. Aljarrah ◽  
Edward A. Evans ◽  
Rex D. Ramsier
Keyword(s):  
Fourier Transformation ◽  
Annealing Temperature ◽  
Electrospun Nanofibers ◽  
Optical Emission ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Conditions ◽  
Near Ir ◽  
Transmission Electron

AbstractErbium(III) doped TiO2 nanofibers (Er2Ti2O7) have been synthesized by electrospinning mixtures of polymers, metal-containing materials, and erbium acetate. These electrospun nanofibers were subsequently annealed at temperatures of 550, 750, 950, and 1150 oC to remove the organics and leave behind the metal oxides. The crystal structure and optical properties of the nanofiber pyrochlores were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transformation IR (FTIR) spectroscopy. Different crystal structures were formed by controlling the annealing conditions. XRD data are compared with near-IR spectra to better understand the effects of annealing temperature on the Er (III) thermally-excited selective optical emission process.

Thermal Annealing-Activated Crystallinity Metastasis of Al:ZnO Thin Films

2015 ◽  
Vol 1109 ◽  
pp. 181-185 ◽  
Author(s):  
Mohd Firdaus Malek ◽  
Mohamad Hafiz Mamat ◽  
M.Z. Musa ◽  
M. Rusop
Keyword(s):  
Thin Films ◽  
Thermal Annealing ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dip Coating Technique ◽  
Multilayered Thin Films

Multilayered thin films of aluminum-doped ZnO (Al:ZnO) have been deposited by the sol-gel dip coating technique. Experimental results indicated that the thermal annealing temperature affected the crystallinity of the Al:ZnO films. X-ray diffraction (XRD) analysis showed that thin films were preferentially orientated along the c-axis plane. The preferred orientation along (0 0 2) plane becomes more pronounced as the thermal annealing being increased. The film thickness ranges between 180 and 690 nm. In our experiments, the most optimum condition of Al:ZnO annealing temperature was both 500 oC.

The Construction of the Heterostructural Bi2O3/g-C3N4 Composites with an Enhanced Photocatalytic Activity

NANO ◽  
2018 ◽  
Vol 13 (06) ◽  
pp. 1850063 ◽  
Author(s):  
Jinhua Zhang ◽  
Huiyue Qian ◽  
Wencheng Liu ◽  
Hao Chen ◽  
Yang Qu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Photogenerated Electron ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Air Atmosphere ◽  
Transmission Electron ◽  
Ft Ir ◽  
The One

A heterostructural composite composed of g-C3N4 and Bi2O3 was achieved by the one-pot and thermal-induced polycondensation method using melamine and Bi(NO[Formula: see text] as precursor at 550[Formula: see text]C under air atmosphere. The crystalline phase, components and morphologies of the as-prepared composites were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Besides, the photocatalytic activity of composites was evaluated by degrading RhB aqueous solution at room temperature under visible light irradiation. Compared with bulk g-C3N4, the photocatalytic efficiency of the 0.5% Bi2O3/g-C3N4 (Bi–CN) was increased by up to four times. The introduction of Bi2O3 enhances not only the light absorption ability, but also the separation of photogenerated electron–hole pairs.

scholarly journals Модификация структурно-морфологических свойств германия в многослойной нанопериодической структуре Al-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-/Ge с промежуточными слоями Si при отжиге

2021 ◽  
Vol 55 (10) ◽  
pp. 882
Author(s):  
М.В. Байдакова ◽  
Н.А. Берт ◽  
В.Ю. Давыдов ◽  
А.В. Ершов ◽  
А.А. Левин ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Annealing Temperature ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
Bimodal Size Distribution ◽  
X Ray ◽  
Transmission Electron ◽  
Mean Size ◽  
The Mean

Multi-layered nanosized Al2O3/Ge/Si structures manufactured by electron-beam evaporation and annealed at a temperature within the range 700−900◦C are examined using transmission electron microscopy, Raman spectroscopy and X-ray diffraction techniques. The periodic structure with a good layer planarity is confirmed to retain after heat treatment up to 900◦C. At an annealing temperature above 700◦C, nanocrystallites with a bimodal size distribution start to form within initially amorphous Ge layers, the mean size of small crystallites being determined by Ge layer thickness and annealing temperature. An essential loss of Ge from multi-layered structure after 900oC anneal and development of Ge1−x Six solid solution with x up to 0.07 in the nanocrystallites is revealed.

scholarly journals Facile synthesis of Rh/Ti3+-TiO2 nanocomposites and its photodisinfection properties on Staphylococcus aureus under visible-NIR excitation

2020 ◽  
Author(s):  
Jingtao Zhang ◽  
Shurui Liu ◽  
Qinwen Wang ◽  
Jing Yao ◽  
Yin Liu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Near Infrared ◽  
One Pot ◽  
X Ray ◽  
Nir Light ◽  
Transmission Electron ◽  
Response Range ◽  
The One

Abstract In this study, we synthesized a series of rhodium-modified and Ti3+ self-doped TiO2 (Rh/Ti3+-TiO2) nanocomposites via the one-pot method. We prepared samples of Rh/Ti3+-TiO2, which were analyzed using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Electron Spin Resonance (ESR), and Uv-vis-NIR analysis. We found that the ability of TiO2 to absorb near-infrared and visible light was significantly improved by the Rh/Ti3+-TiO2 nanocomposites, due to Ti3+ doping as well as modification of Rh. The disinfection properties of these materials were tested using Staphylococcus aureus under visible light and NIR light excitations. The synthesized photocatalyst was found to exhibit significantly enhanced photocatalytic inactivation of S. aureus under both visible and NIR light irradiation, as compared to pure TiO2. This was particularly true with respect to the 5% Rh/Ti3+-TiO2 sample. Our results suggest that the Rh/Ti3+-TiO2 composites could extend the range of optical response range of pure nano TiO2 materials to the Vis -NIR region.

Characterization of Si Nanocrystals Embedded in SiO2 with X-Ray Photoelectron Spectroscopy

2005 ◽  
Vol 23 ◽  
pp. 11-14
Author(s):  
Y. Liu ◽  
T.P. Chen ◽  
Y.Q. Fu ◽  
J.H. Hsieh
Keyword(s):  
Thermal Annealing ◽  
Photoelectron Spectroscopy ◽  
Significant Shift ◽  
Xps Spectra ◽  
Potential Wells ◽  
X Ray ◽  
Si Nanocrystals ◽  
Charging Effect ◽  
Subsequent Thermal Annealing

X-ray photoelectron spectroscopy (XPS) has been used to characterize the Si nanocrystals (nc-Si) incorporated in SiO2 by ion implantation and subsequent thermal annealing. XPS results suggest that the as-implanted films contain a composition of a few suboxide SiOx (x<2). The dependence of XPS spectra on annealing temperature show that these suboxides decompose into SiO2 and Si nanocrystals. Due to the implanted Si+ depth profile, thermal annealing will lead to the formation of nc-Si with different sizes corresponding to the depth. Si0 peak shifts arising from the size effect of nc-Si can be clearly observed. Photo-induced charge effect from the nc-Si has been studied in this work. The potential wells induced by nc-Si in the SiO2 band gap substantially enhance the charging effect, which causes a significant shift in Si0 and C1s core levels.

A STUDY ON THE PRECIPITATION OF Ge-RICH NANOPARTICLES IN A LUMINESCENT (Er, Ge) CO-DOPED SiO2 FILM SPUTTERED WITH Ar + O2 PLASMA

2006 ◽  
Vol 05 (04n05) ◽  
pp. 493-498
Author(s):  
C. L. HENG ◽  
Y. J. LI ◽  
J. MAYANDI ◽  
T. G. FINSTAD ◽  
S. JØRGENSEN ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Rf Magnetron Sputtering ◽  
Sio2 Film ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Amorphous States ◽  
Co Doped

We report the photoluminescence (PL) from an ( Er , Ge ) co-doped SiO 2 film deposited by rf-magnetron sputtering in an Ar + O 2 ambience. The sample film was annealed in N 2 for 30 min at different temperatures. The PL intensity increases as the annealing temperature increases from 700 to 1000°C, and drops to very weak after 1100°C annealing. High-resolution transmission electron microscopy (TEM) observation shows that there are some Ge -rich nanoparticles precipitated after 700°C annealing, and more clusters precipitated after 1000°C annealing. However, no Ge nanocrystals were found in these films, the diffraction patterns are always halo which indicates that the precipitated clusters are in amorphous states. X-ray photoelectron spectroscopy (XPS) analysis indicates the Ge in the nanoclusters is mostly in an oxidized state and the oxidation state of Er increases with increasing annealing temperature.

Optical Features of the Silica Sol–Gel Derived Glasses Doped with Copper Selenide Nanoparticles

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940021
Author(s):  
V. S. Gurin ◽  
A. A. Alexeenko
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Silica Sol ◽  
Copper Selenide ◽  
Optical Absorption Spectroscopy ◽  
X Ray ◽  
Copper Chalcogenides ◽  
Near Ir ◽  
Transmission Electron ◽  
Variable Stoichiometry

In the field of semiconductor nanooptics, copper chalcogenides have challenged a novel direction associated with nontrivial optical features in the near IR range important for applications. We consider this phenomenon in the silica sol–gel derived glasses doped with copper selenide nanoparticles. They were characterized with transmission electron microscopy, X-ray photoelectron spectroscopy and optical absorption spectroscopy. An origin of the near IR optical features is discussed involving both the plasmon resonance concept extended to the self-doping of chalcogenides with a variable stoichiometry and the effect of Cu2+ impurity-generated intraband levels providing linear and nonlinear optical response of these materials.

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